Stability of Thin Cylindrical Shells in Torsion

Beginning with previously derived general differential equations, this paper leads to the development of a single continuous expression for the critical shearing stress at buckling for all cylindrical shells or tubes whether long, medium, or short. This expression is reduced to a simple equation and a family of curves dependent only on the geometry of the shells and independent of the properties of the materials of which the shell is constructed. The simple equation introduces all factors dependent on the shell material. Comparisons between test results and theoretical values show excellent agreement. Methods for computing the strength of imperfect or incomplete shells are derived and compared with test results. A method of specifying maximum out-of-roundness or local discrepancies for a give n percentage of strength is also proposed. A procedure for determining critical shearing stresses in thin-walled pipelines, tanks, or fuselages is presented.